It is necessary to periodically repair metallurgical vessels because the lining thereof deteriorates over time and, in the case of bottom blown steel converters, it is necessary to periodically repair the bottom asembly by rebuilding the refractory bottom and/or replacing tuyeres. It is desirable that bottom removal or vessel relining be accomplished in a minimal amount of time in order to minimize disruption of production. Hand methods of vessel bottom replacement and furnace relining are very time consuming and require a considerable number of workmen.
Methods are known for facilitating the removal and replacement of the bottom assemblies of bottom blown vessels. One such method is described in Fisher et al. U.S. Pat. No. 3,944,083 issued Mar. 16, 1976 for "Bottom Handling Apparatus for Steel Converter Vessels". The bottom handling apparatus comprises a movable frame assembly mounted, for example, on a ladle car and the assembly includes a support surface and hydraulic cylinders for positioning the support below the vessel. Means are provided for providing a downward breakaway force on the vessel bottom to release same. In an alternate embodiment, a plurality of jacks are provided on the vessel bottom itself for exerting a breakaway force between the vessel and the vessel bottom assembly.
While the apparatus described in this patent is considerably more efficient than hand methods, the vessel itself is still out of use during the time required for removal of the bottom, the time required for the car to transport the bottom assembly to a repair station, deposit it there, travel to a different repair station, load a repaired bottom assembly, transport the latter to the vessel and the time required for the work crew to install the new bottom. Moreover, the apparatus described in this patent is not designed for improving the efficiency of repair of replacement of the vessel lining.
Downtime problems are especially important in smaller melt shops which have only a single refining station. In these shops, the downtime causes a total shut-down of production and a large waste of employee time. Downtime in such shops can last for days and a solution to the problem would result in a significant advance in this technology. A solution to this problem must take into account the space requirements of such melt shops and must not interfere with the other metallurgical apparatus generally located in such plants.